1. What is force?
1.1. Force is a push or pull upon an object resulting from the object's interaction with another object
1.2. Force is the capacity to do work or cause physical change
1.3. Forces make objects start or stop moving – like when you kick or stop a football, you need to put a force on the ball with your foot.
1.4. Forces can also change an object's shape – like when you crush an empty drinks can.
1.5. The harder you push something, the more force you are applying to it.
2. Effects of forces
2.1. It can change the size or shape of an object
2.2. It can move a stationary object.
2.3. It can stop a moving object.
2.4. It can change the direction of a moving object.
2.5. It can accelerate or decelerate a moving object.
3. How to measure force?-
3.1. We can measure force using a force meter
3.2. One example of a force meter is a elastic spring balance, which those people who collect newspapers from your house, use.
4. What is Pressure?
4.1. Pressure is the force per unit area applied in a direction perpendicular to the surface of the object.
4.2. The symbol used to represent pressure is p.
4.3. Pressure depends on the force applied and the area of the object.
5. How to increase pressure?
5.1. The pressure increase when the force applied on the object increased or the area of the object increase.
5.2. One example by increasing the pressure by reducing the area of the object is a sharp knife and a blunt on. The sharp knife has a small area in contact with the object, causing the pressure to be higher than the blunt one. Therefore, it is easier to cut things using a sharp knife in comparison to a blunt one.
6. How to calculate pressure?
6.1. Pressure is calculated by the amount of force applied onto the object divide by the area of the object. (To calculate force, you have to take the mass of the object multiply with the acceleration of the object.) (To find the acceleration of an object, you need to have the amount of friction applied on the object(in amount of Newton) divide the metre of the object.
7. The work example to calculate the pressure of an object.
7.1. There is a block on a bench. The mass of block is 8kg. The weight of the block (the force on the bench) is 80 newtons. The base area of the block is 2 square metre. So the pressure on the bench is 80 ÷ 2 = 40 Pascals.
8. Important Forces in our everyday life
8.1. Frictional Force
8.1.1. Frictional force is produced when the surface of one object coming into contact with the surface of another object
8.1.2. Frictional Force is very important in our life as it enables us the walk easily on earth.
8.1.3. Frictional Force can also be dangerous as when two surfaces are rubbed together, heat is usually generated.
8.1.4. The useful effects of friction is that it enable us to walk, hold things.
8.1.5. The negative effects of friction is that car tyres got wore out, shoes get worn out and there would be wear and tear in machines.
8.1.6. Ways to reduce friction: -Using lubricant -Using ball bearings -Smoothing the surface by polishing -Streamlining
8.2. Magnetic Force
8.2.1. Magnetic Force is a force exerted by a magnet.
8.2.2. An example of objects which make use of magnetic force is the crane as it uses a powerful magnet to lift iron and steel objects.
8.2.3. A magnet can also exert a force on another magnet. Example: The like poles of the magnet repel each other while the unlike poles of the magnet attracts each other. So by doing that, they are exerting a force.
8.3. Gravitational Force
8.3.1. Gravitational Force (a.k.a. Gravity Force) is a force that pulls objects towards the Earth. It can exists between any two objects.
8.3.2. Gravitational Force is one of the main reason we are standing and not floating up in the space.